Substituted benzimidazolium compounds useful in the treatment of respiratory diseases

ABSTRACT

The present invention relates to compounds of formula (I), or the tautomers or pharmacologically acceptable acid addition salts thereof, wherein R 1 , R 2 , R 3 , R 4 , X, and Z have one of the meanings as defined in the specification, to the use of compounds of formula (I) as a medicament, to pharmaceutical composition comprising at least one compound of formula (I), as well as to medicament combinations containing one or more compounds of formula (I).

FIELD OF THE INVENTION

The present invention relates to compounds of formula (I), or the tautomers or pharmacologically acceptable acid addition salts thereof,

wherein R¹, R², R³, R⁴, X, and Z⁻ have one of the meanings as defined in the specification, to the use of compounds of formula (I) as a medicament, to pharmaceutical compositions comprising at least one compound of formula (I), as well as to medicament combinations containing one or more compounds of formula (I).

BACKGROUND TO THE INVENTION

WO2011079087 discloses compounds of similar structure showing ENaC (Epithelial Sodium Channel) inhibitor activity.

The problem of the present invention is to prepare new compounds which may be used therapeutically for the treatment of pathophysiological processes treatable by the blockade of an epithelial sodium channel, particularly for the treatment of the lungs and airways. The new compounds of the present invention exhibit a longer lasting activity in topical lung treatment. The new compounds of the present invention further exhibit a reduced permeability being beneficial for topical lung treatment.

DETAILED DESCRIPTION OF THE INVENTION

The present invention relates to compounds of formula (I), or the tautomers or pharmacologically acceptable acid addition salts thereof,

wherein

-   R¹ is selected from C₁-C₃-alkyl, tetrahydrofurylmethyl, and     H(OCH₂CH₂)_(n), wherein n is 1, 2, or 3; -   R² is selected from C₁-C₃-alkyl; -   R³ is selected from —C(O)NR_(a)R_(b), —CH₂—C(O)NR_(a)R_(b), and     —O—CH₂—C(O)NR_(a)R_(b), wherein     -   at least one R^(a) or R^(b) is selected from         C₁-C₂-alkoxy-C₂-C₃-alkyl, amino-C₂-C₃-alkyl, 4-piperidinyl,         dimethylamino-C₂-C₃-alkyl,         1-(C₁-C₄-alkoxycarbonylamino)-C₂-C₃-alkyl,         1-(C₁-C₄-alkoxy-carbonyl)-4-piperidinyl,         3-hydroxy-2-pyridylmethyl and         3-hydroxy-6-methyl-2-pyridylmethyl; and wherein     -   the remaining substituent R^(a) or R^(b) may additionally be         selected from H, C₁-C₃-alkyl, hydroxyethyl, or hydroxypropyl; or         wherein     -   R^(a) and R^(b) together with the nitrogen atom they are         attached to form a heterocyclic ring selected from piperazine,         and pyrrolidine, wherein the heterocyclic ring may carry 1 or 2         substituents selected from methyl, OH, and C₁-C₄-alkoxycarbonyl;         or wherein -   R³ is selected from C₁-C₃-alkoxy substituted by 1 or 2 substituents     selected from OH and C₁-C₃-alkoxy; -   R⁴ is selected from H, Cl, Br, pyrrolyl, pyridinyl, and     N-morpholinyl, wherein pyrrolyl, and pyridinyl may optionally carry     1 or 2 substituents selected from C₁-C₃-alkyl,     1-methylpiperazin-4-yl, tetrahydropyran-4-yloxy), and     morpholin-4-yl-C₂-C₃-alkyl; -   X is Cl or Br; and -   Z⁻ is chloride, bromide, iodide, hydroxide, hydrogensulfate,     sulfate, nitrate, phosphate, formate, acetate, trifluoroacetate,     fumarate, citrate, tartrate, oxalate, succinate, mandelate,     methanesulfonate or p-toluenesulfonate; or -   Z− may be absent if the remaining compound of formula (I) carries at     least one negatively charged substituent R³ or R⁴.

The compounds of formula (I) according to the present invention are usually characterized by a topological polar surface area value (TPSA) of at least 145. The term “topological polar surface area” as used herein refers to a value calculated as described in Ertl P. et al., J. Med. Chem, 43 (2000), 3714-3717. Suitable compounds of formula (I) will usually have a TPSA value in the range of from 145 to 250.

The compounds of formula (I) or the tautomers or pharmacologically acceptable acid addition salts thereof as defined herein are particularly suitable for the treatment of pathophysiological processes treatable by the blockade of an epithelial sodium channel, particularly for the treatment of the lungs and airways.

Accordingly the present invention further relates to compounds of formula (I) as defined herein or the tautomers or pharmacologically acceptable acid addition salts thereof for use as a medicament.

The present invention further relates to compounds of formula (I) as defined herein or to the tautomers or pharmacologically acceptable acid addition salts thereof for use in the treatment of a disease selected from among respiratory diseases or complaints and allergic diseases of the airways.

The present invention further relates to compounds of formula (I) as defined herein or to the tautomers or pharmacologically acceptable acid addition salts thereof for use in the treatment of a disease selected from among chronic bronchitis, acute bronchitis, bronchitis caused by bacterial or viral infection or fungi or helminths, allergic bronchitis, toxic bronchitis, chronic obstructive bronchitis (COPD), asthma (intrinsic or allergic), pediatric asthma, bronchiectasis, allergic alveolitis, allergic or non-allergic rhinitis, chronic sinusitis, cystic fibrosis or mucoviscidosis, alpha-1-antitrypsin deficiency, cough, pulmonary emphysema, interstitial lung diseases, alveolitis, hyperreactive airways, nasal polyps, pulmonary oedema, pneumonitis of different origins, and dry eyes.

The present invention further relates to a pharmaceutical composition comprising at least one compound of formula (I) as defined herein or the tautomers or pharmacologically acceptable acid addition salts thereof and a pharmaceutically acceptable carrier.

The present invention further relates to medicament combinations containing besides one or more compounds of formula (I) as defined herein or the tautomers or pharmacologically acceptable acid addition salts thereof, as further active substance one or more compounds selected from among the categories of further ENaC inhibitors, betamimetics, anticholinergics, corticosteroids, PDE4-inhibitors, LTD4-antagonists, EGFR-inhibitors, dopamine agonists, H1 antihistamines, PAF-antagonists, MAP-kinase inhibitors, MPR4-Inhibitors, iNOS-Inhibitors, SYK-Inhibitors, corrections of the cystic fibrosis transmembrane regulator (CFTR) and CFTR potentiators or double or triple combinations thereof.

Terms and Definitions

Terms not specifically defined herein should be given the meanings that would be given to them by one of skill in the art in light of the disclosure and the context. As used in the specification, however, unless specified to the contrary, the following terms have the meaning indicated and the following conventions are adhered to.

In the groups, radicals, or moieties defined below, the number of carbon atoms is often specified preceding the group, for example, C₁₋₆-alkyl means an alkyl group or radical having 1 to 6 carbon atoms.

In general in single groups like HO, H₂N, OS, O₂S, NC (cyano), HOOC, F₃C or the like, the skilled arti-san can see the radical attachment point(s) to the molecule from the free valences of the group itself. For combined groups comprising two or more subgroups, the terminal term indicates the radical attachment point, for example, the substituent “aryl-C₁₋₃-alkyl” means an aryl group which is bound to a C₁₋₃-alkyl-group, the latter of which is bound to the core or to the group to which the substituent is attached.

In case a compound of the present invention is depicted in form of a chemical name and as a formula, in case of any discrepancy the formula shall prevail.

Many of the following terms may be used repeatedly in the definition of a formula or group and in each case have one of the meanings given above, independently of one another.

Unless specifically indicated, according to the invention a given chemical formula or name shall encom-pass tautomers and all stereo, optical and geometrical isomers (e.g. enantiomers, diastereomers, E/Z isomers etc.) and racemates thereof as well as mixtures in different proportions of the separate enantiomers, mixtures of diastereomers, or mixtures of any of the foregoing forms where such isomers and enantiomers exist, as well as salts, including pharmaceutically acceptable salts thereof and solvates thereof such as for instance hydrates including solvates of the free compounds or solvates of a salt of the compound.

The term “substituted” as used herein, means that any one or more hydrogens on the designated atom is replaced with a selection from the indicated group, provided that the designated atom's normal valence is not exceeded, and that the substitution results in a stable compound.

By the term “optionally substituted” is meant within the scope of the invention the above-mentioned group, optionally substituted by a lower-molecular group. Examples of lower-molecular groups regarded as chemically meaningful are groups consisting of 1-200 atoms. Preferably such groups have no negative effect on the pharmacological efficacy of the compounds. For example the groups may comprise: Straight-chain or branched carbon chains, optionally interrupted by heteroatoms, optionally substituted by rings, heteroatoms or other common functional groups.

The expressions “prevention”, “prophylaxis”, “prophylactic treatment” or “preventive treatment” used herein should be understood synonymous and in the sense that the risk to develop a condition mentioned s1 hereinbefore is reduced, especially in a patient having elevated risk for said conditions or a corresponding anamnesis, e.g. elevated risk of developing metabolic disorder such as diabetes or obesity or another disorder mentioned herein. Thus the expression “prevention of a disease” as used herein means the management and care of an individual at risk of developing the disease prior to the clinical onset of the disease. The purpose of prevention is to combat the development of the disease, condition or disorder, and includes the administration of the active compounds to prevent or delay the onset of the symptoms or complications and to prevent or delay the development of related diseases, conditions or disorders. Success of said preventive treatment is reflected statistically by reduced incidence of said condition within a patient population at risk for this condition in comparison to an equivalent patient population without preventive treatment.

The expression “treatment” or “therapy” means therapeutic treatment of patients having already developed one or more of said conditions in manifest, acute or chronic form, including symptomatic treatment in order to relieve symptoms of the specific indication or causal treatment in order to reverse or partially reverse the condition or to delay the progression of the indication as far as this may be possible, depending on the condition and the severity thereof. Thus the expression “treatment of a disease” as used herein means the management and care of a patient having developed the disease, condition or disorder. The purpose of treatment is to combat the disease, condition or disorder. Treatment includes the administration of the active compounds to eliminate or control the disease, condition or disorder as well as to alleviate the symptoms or complications associated with the disease, condition or disorder.

The term “pharmacologically acceptable” is employed herein to refer to those compounds, materials, compositions, and/or dosage forms which are, within the scope of sound medical judgment, suitable for use in contact with the tissues of human beings and animals without excessive toxicity, irritation, allergic response, or other problem or complication, and commensurate with a reasonable benefit/risk ratio.

As used herein, “pharmacologically acceptable salts” refer to derivatives of the disclosed compounds wherein the parent compound is modified by making acid or base salts thereof. Examples of pharmacologically acceptable salts include, but are not limited to, mineral or organic acid salts of basic residues such as amines; alkali or organic salts of acidic residues such as carboxylic acids; and the like. For example, such salts include salts from ammonia, L-arginine, betaine, benethamine, benzathine, calcium hydroxide, choline, deanol, diethanolamine (2,2′-iminobis(ethanol)), diethylamine, 2-(diethylamino)-ethanol, 2-aminoethanol, ethylenediamine, N-ethyl-glucamine, hydrabamine, 1H-imidazole, lysine, magnesium hydroxide, 4-(2-hydroxyethyl)-morpholine, piperazine, potassium hydroxide, 1-(2-hydroxyethyl)-pyrrolidine, sodium hydroxide, triethanolamine (2,2′,2″-nitrilotris(ethanol)), tromethamine, zinc hydroxide, acetic acid, 2,2-dichloro-acetic acid, adipic acid, alginic acid, ascorbic acid, L-aspartic acid, benzene-sulfonic acid, benzoic acid, 2,5-dihydroxybenzoic acid, 4-acetamido-benzoic acid, (+)-camphoric acid, (+)-camphor-10-sulfonic acid, carbonic acid, cinnamic acid, citric acid, cyclamic acid, decanoic acid, dodecylsulfuric acid, ethane-1,2-disulfonic acid, ethanesulfonic acid, 2-hydroxy-ethanesulfonic acid, ethylenediaminetetraacetic acid, formic acid, fumaric acid, galactaric acid, gentisic acid, D-glucoheptonic acid, D-gluconic acid, D-glucuronic acid, glutamic acid, glutaric acid, 2-oxo-glutaric acid, glycerophosphoric acid, glycine, glycolic acid, hexanoic acid, hippuric acid, hydrobromic acid, hydrochloric acid, isobutyric acid, DL-lactic acid, lactobionic acid, lauric acid, lysine, maleic acid, (−)-L-malic acid, malonic acid, DL-mandelic acid, methanesulfonic acid, galactaric acid, naphthalene-1,5-disulfonic acid, naphthalene-2-sulfonic acid, 1-hydroxy-2-naphthoic acid, nicotinic acid, nitric acid, octanoic acid, oleic acid, orotic acid, oxalic acid, palmitic acid, pamoic acid (embonic acid), phosphoric acid, propionic acid, (−)-L-pyroglutamic acid, salicylic acid, 4-amino-salicylic acid, sebacic acid, stearic acid, succinic acid, sulfuric acid, tannic acid, (+)-L-tartaric acid, thiocyanic acid, p-toluenesulfonic acid and undecylenic acid. Further pharmaceutically acceptable salts can be formed with cations from metals like aluminium, calcium, lithium, magnesium, potassium, sodium, zinc and the like. (also see Pharmaceutical salts, Berge, S. M. et al., J. Pharm. Sci., (1977), 66, 1-19).

The pharmacologically acceptable salts of the present invention can be synthesized from the parent compound which contains a cationic group and optionally an additional basic or acidic moiety by conventional chemical methods. Generally, such salts can be prepared by reacting other salt forms of these compounds with a sufficient amount of the appropriate base or acid in water or in an organic diluent like ether, ethyl acetate, ethanol, isopropanol, or acetonitrile, or a mixture thereof. Moreover, counterions can generally be exchanged by ion exchange chromatography.

Salts of other acids than those mentioned above which for example are useful for purifying or isolating the compounds of the present invention (e.g. trifluoro acetate salts) also comprise a part of the invention.

The term “C_(1-n)-alkyl”, wherein n is an integer from 2 to n, either alone or in combination with another radical denotes an acyclic, saturated, branched or linear hydrocarbon radical with 1 to n C atoms. For example the term C₁₋₅-alkyl embraces the radicals H₃C—, H₃C—CH₂—, H₃C—CH₂—CH₂—, H₃C—CH(CH₃)—, H₃C—CH₂—CH₂—CH₂—, H₃C—CH₂—CH(CH₃)—, H₃C—CH(CH₃)—CH₂—, H₃C—C(CH₃)₂—, H₃C—CH₂—CH₂—CH₂—CH₂—, H₃C—CH₂—CH₂—CH(CH₃)—, H₃C—CH₂—CH(CH₃)—CH₂—, H₃C—CH(CH₃)—CH₂—CH₂—, H₃C—CH₂—C(CH₃)₂—, H₃C—C(CH₃)₂—CH₂—, H₃C—CH(CH₃)—CH(CH₃)— and H₃C—CH₂—CH(CH₂CH₃)—.

The term “C₁₋₆-alkoxy” (including those which are part of other groups) denotes branched and unbranched alkoxy groups with 1 to 6 carbon atoms and the term “C₁₋₄-alkoxy” denotes branched and unbranched alkoxy groups with 1 to 4 carbon atoms. Alkoxy groups with 1 to 4 carbon atoms are preferred. Examples include: methoxy, ethoxy, propoxy, butoxy or pentoxy. The abbreviations OMe, OEt, OPr, etc. may optionally be used for the above-mentioned groups. Unless stated otherwise, the definitions propoxy, butoxy s15 and pentoxy include all the possible isomeric forms of the respective groups. Thus for example propoxy includes n-propoxy and iso-propoxy, butoxy includes iso-butoxy, sec-butoxy and tert-butoxy etc.

In all cases of contradictions between structure and their naming, structure shall prevail.

PREFERRED EMBODIMENTS

A particular embodiment of the present invention relates to compounds of formula (I) as defined herein or the tautomers or pharmacologically acceptable acid addition salts thereof, wherein R³ is selected from —C(O)NR_(a)R_(b). Examples of suitable substituents of formula —C(O)NR_(a)R_(b) are

wherein

denotes the point of attachment.

Another particular embodiment of the present invention relates to compounds of formula (I) as defined herein or to the tautomers or pharmacologically acceptable acid addition salts thereof, wherein R³ is selected from —O—CH₂—C(O)NR_(a)R_(b). Examples of suitable substituents of formula —O—CH₂—C(O)NR_(a)R_(b) are

wherein

denotes the point of attachment.

Another particular embodiment of the present invention relates to compounds of formula (I) as defined herein or to the tautomers or pharmacologically acceptable acid addition salts thereof, wherein R³ is selected from 1-hydroxymethyl-2-hydroxyethoxy and 2-methoxyethoxy.

Another particular embodiment of the present invention relates to compounds of formula (I) as defined herein or to the tautomers or pharmacologically acceptable acid addition salts thereof, wherein R⁴ is selected from 1,3-dimethylpyrazol-4-yl, 1-(morpholin-4-yleth-2-yl)pyrazol-4-yl, pyridinyl, methylpyridinyl, 2-(1-methylpiperazin-4-yl)pyridin-5-yl, and 2-(tetrahydropyran-4-yloxy)pyridin-5-yl.

The present invention relates to compounds of formula (I) as defined herein or to the tautomers or pharmacologically acceptable acid addition salts thereof, wherein Z⁻ is chloride, bromide, iodide, hydroxide, hydrogensulfate, sulfate, nitrate, phosphate, formate, acetate, trifluoroacetate, fumarate, citrate, tartrate, oxalate, succinate, mandelate, methanesulfonate or p-toluenesulfonate, or wherein Z⁻ may be absent if the remaining compound of formula (I) carries at least one negatively charged substituent R³ or R⁴. If Z⁻ is selected from anions carrying more than one negative charge, such as fumarate, citrate, tartrate, oxalate, or succinate, Z⁻ may represent the monovalent equivalent part of such an anion. Alternatively, Z⁻ may represent the respective partially protonated form, such as hydrogenfumarate, hydrogencitrate, dihydrogencitrate, hydrogentartrate, etc. Further in this context the term “negatively charged substituent R³ or R⁴ is meant to include substituents which at a neutral pH-value are to a substantial extent present in deprotonated form, i.e. substituents having a pKa value of 9 or lower, such as carboxygroups or acidic hydroxyl substituents.

A particular embodiment of the present invention relates to compounds of formula (I) as defined herein or the tautomers or pharmacologically acceptable acid addition salts thereof, wherein Z⁻ is chloride, or trifluoroacetate or Z⁻ may be absent if the remaining compound of formula (I) carries at least one negatively charged substituent R³ or R⁴.

Any substituent defined above may be combined with any other substituent defined above. Particularly preferred are compounds of formula (I) or the pharmaceutically acceptable salts thereof wherein at least 2, 3, 4, 5, 6 or 7 of the substituents defined herein have one of the particular or preferred meaning as defined herein.

Preparation

The following methods are suitable for preparing compounds of general formula (I).

The compounds according to the invention may be obtained using methods of synthesis which are known to the one skilled in the art and described in the literature of organic synthesis. General methods for functional group protection and deprotection are described e.g. in: Greene, T. W. and Wuts, P.G.M. (eds.): Protective Groups in Organic Synthesis, third edition 1999; John Wiley and Sons, Inc. Preferably the compounds are obtained analogously to the methods of preparation explained more fully hereinafter, in particular as described in the experimental section.

Compounds of general formula (I) can be prepared by standard amidation procedures from amines of general formula (II) and the approprioate 3,5-diaminopyrazine-2-carboxylic acid applying e.g. the coupling reagent HATU. Amines (II) can be prepared from N-protected precursors of general formula (III) by standard deprotection procedures. Suitable protecting groups in (III) are e.g. BOC (wherein R^(PG) denotes —NHPG with PG denoting tert-BuOC(O)—) and phthaloyl (wherein R^(PG) denotes phthalimide). Compounds (III) can be prepared by alkylation of benzimidazoles of general formula (IIIa) applying alkylating agents R¹-LG. The leaving group LG can be e.g. Br or I.

Alternatively, compounds of general formula (I) can be prepared by alkylation of benzimidazoles of general formula (Ia) applying alkylating agents R¹-LG. The leaving group LG can be e.g. Br or I. Compounds of general formula (Ia) can be prepared by standard amidation procedures from amines of general formula (IIa) and the appropriate 3,5-diaminopyrazine-2-carboxylic acid applying e.g. the coupling reagent HATU. Amines (IIa) can be prepared from N-protected precursors of general formula (IIIa) by standard deprotection procedures. Suitable protecting groups in (IIIa) are e.g. BOC (wherein R^(PG) denotes —NHPG with PG denoting tertBu-OC(O)—) and phthaloyl (wherein RPG denotes phthalimide).

Benzimidazoles (IIIa) can be prepared from phenylenediamines (IV) in a two step procedure comprising (i) amidation with N-protected glycine using e.g. the coupling reagent TBTU and (ii) ring closure under acid catalysis, e.g. in glacial acetic acid at elevated temperature.

Phenylenediamines can be prepared from the respective nitroanilines (V) by standard nitro reduction conditions (e.g. catalytic hydrogenation using raney-nickel as a catalyst).

Compounds (V) can be prepared from derivatives (VI) by nucleophilic substitution of the leaving group LG (e.g. F or Cl) with a primary amine R²—NH₂ as nucleophile. Alternatively, compounds (V) can be accessed from nitroanilines (Va) by either alkylation (using an alkylating agent R²-LG) or reductive amination (using an appropriate aldehyde) of the aromatic amino group.

Compounds (I), (la), (III), (IIIa) and (V) can be modified using methods of synthesis which are known to the one skilled in the art and described in the literature of organic synthesis, preferably by functional group protection or deprotection steps, esterifications, amidation, hydrogenations, or 1,3-dipolar cycloadditions. Thereby, before such a modification, the structures of R¹, R², R³, and R⁴ may be beyond of what is claimed hereinafter.

The skilled person will appreciate that within these general synthesis schemes, the substituents R¹ and R² can in principle be interchanged, meaning that R² instead of R¹ can be introduced in the late alkylation step applying an alkylating agent R²-LG.

Compounds of formula (I), as defined hereinbefore, are salts containing an anion Z⁻. These anions Z⁻ may be derived from synthesis or purification or changed from one anionic species to another suitable anionic species by methods known to those skilled in the art. Examples of such methods are ion exchange using for example ion exchange resins or displacement of an acid counterion from its salt using another, usually stronger, acid. For example, treatment of a compound of formula (I), as defined hereinbefore, where Z⁻ is CF₃COO⁻, with HCl in a suitable solvent, such as water, methanol or diethyl ether, may produce a compound of formula 1, as defined hereinbefore, where Z⁻ is Cl⁻.

Certain compounds of formula (I), as defined hereinbefore, may contain groups that may be further converted into the salts thereof, for pharmaceutical use particularly into pharmaceutically acceptable salts with inorganic or organic acids and bases. Acids which may be used for this purpose include for example hydrochloric acid, hydrobromic acid, sulphuric acid, methanesulphonic acid, phosphoric acid, fumaric acid, succinic acid, lactic acid, citric acid, tartaric acid or maleic acid. Corresponding processes are known to the skilled person.

Moreover, where one or more stereoisomers may exist, the compounds of general formula (I) or intermediates in the synthesis of compounds of general formula (I) may be obtained as mixtures and then resolved into their stereoisomers, e.g. enantiomers and/or diastereomers. Thus, for example, cis/trans mixtures may be resolved into their cis and trans isomers, and racemic compounds may be separated into their enantiomers.

Thus, for example, the cis/trans mixtures may be resolved by chromatography into the cis and trans isomers thereof. The compounds of general formula (I) or intermediates in the synthesis of compounds of general formula 1, which occur as racemates may be separated by methods known per se (cf. Allinger N. L. and Eliel E. L. in “Topics in Stereochemistry”, Vol. 6, Wiley Interscience, 1971) into their optical antipodes and compounds of general formula 1 or intermediates in the synthesis of compounds of general s1 formula (I) with at least 2 asymmetric carbon atoms may be resolved into their diastereomers on the basis of their physical-chemical differences using methods known per se, e.g. by chromatography and/or fractional crystallisation, and, if these compounds are obtained in racemic form, they may subsequently be resolved into the enantiomers as mentioned above.

The racemates are preferably resolved by column chromatography on chiral phases or by crystallization from an optically active solvent or by reacting with an optically active substance which forms salts or derivatives such as esters or amides with the racemic compound. Salts may be formed with enantiomerically pure acids for basic compounds and with enantiomerically pure bases for acidic compounds. Diastereomeric derivatives are formed with enantiomerically pure auxiliary compounds, e.g. acids, their activated derivatives, or alcohols. Separation of the diastereomeric mixture of salts or derivatives thus obtained may be achieved by taking advantage of their different physico-chemical properties, e.g. differences in solubility; the free antipodes may be released from the pure diastereomeric salts or derivatives by the action of suitable agents. Optically active acids in common use for such a purpose are e.g. the D- and L-forms of tartaric acid, dibenzoyltartaric acid, ditoloyltartaric acid, malic acid, mandelic acid, camphor-sulfonic acid, glutamic acid, aspartic acid, or quinic acid. Optically active alcohols applicable as auxiliary residues may be, for example, (+) or (−)-menthol and optically active acyl groups in amides may be, for example, (+)- or (−)-menthyloxycarbonyl.

The substances according to the invention are isolated and purified in a manner known per se, for example by distilling off the solvent under reduced pressure and recrystallizing the residue obtained from a suitable solvent or subjecting it to one of the customary purification methods, such as, for example, column chromatography on a suitable support material.

The compounds according to the invention are advantageously obtainable using the methods described in the examples that follow, which may also be combined for this purpose with methods known to the skilled person from his/her expert knowledge. Likewise, further compounds according to this invention, whose preparation are not explicitly described in the following examples, can be prepared analogously or similarly to the examples.

EXAMPLES

The following examples illustrate the present invention without restricting its scope.

Other features and advantages of the present invention will become apparent from the following more detailed Examples which illustrate, by way of example, the principles of the invention.

Where no salt forms of compounds are specified, the compound may exist as a free base or a salt or a zwitterion, depending on the chemical structure, the synthesis conditions and the processes of workup and purification applied. The skilled person will appreciate that the compound is not limited to a certain salt form. Where salt forms of compounds are specified, the stoichiometry of the counterion is usually omitted. In case of multiply charged counterions the skilled person will appreciate that the resulting salt form is uncharged, leading to the corresponding stoichiometry. The skilled person will appreciate that the compound is not limited to the mono salt form and that it may exist as a disalt, trisalt or other compound: counterion stoichiometries. Furthermore, the skilled person will appreciate that such compound may unexpectedly exist as a salt with a different counterion, depending on the synthesis conditions and the processes of workup and purification applied. Solely for the purpose of yield determination, an estimate of the nature of the counterion and of compound: counterion stoichiometry is made (as indicated by the formula given).

Synthesis of Intermediates Intermediate A. 1: 3,5-diamino-6-chloropyrazine-2-carboxylic acid

A mixture of methyl 3,5-diamino-6-chloropyrazine-2-carboxylate (100 g; 494 mmol), methanol (1 μl) and NaOH (6 mol/l in water; 240 ml; 1.44 mol) is refluxed for 3 h. The mixture is allowed to cool to r.t. and then neutralized by addition of hydrochloric acid (6 mol/l in water; approx. 240 mL). Water (200 ml) is added. The precipitate formed is filtered off with suction, washed with water and dried at 60° C.

C₅H₅ClN₄O₂ ESI Mass spectrum: m/z=189 [M+H]+; m/z=187 [M−H]⁻

Intermediate A.2: 3,5-diamino-6-bromopyrazine-2-carboxylic acid

A.2 is prepared from methyl 3,5-diamino-6-bromopyrazine-2-carboxylate (which is prepared from methyl 3,5-diamino-6-chloropyrazine-2-carboxylate as described in J. Med. Chem. 10 (1967) 66-75) analogously to the procedure described for the synthesis of intermediate A.1

Intermediate I.1

A mixture of 3-fluoro-2-nitro-phenol (1.00 g; 6.37 mmol), tert-butyl chloroacetate (1.82 ml; 12.7 mmol) and potassium carbonate (1.76 g; 12.7 mmol) in ACN is refluxed for 5 h. The mixture is evaporated and the residue is purified by silica gel chromatography (eluent: CH/EE 0->25%).

C₁₂H₁₄FNO₅ ESI Mass spectrum: m/z=272 [M+H]+

The following intermediates are prepared accordingly from the respective phenol and the respective alkyl halide as indicated. Depending upon conditions applied, the syntheses may yield a free base, a TFA salt or other salt forms which can be applied equally to the syntheses of example compounds described below.

Synthesis Intermediate Structure phenol applied alkyl halide applied comment I.2

2-bromo-ethyl methyl ether Solvent: ethanol

Intermediate II.1

A mixture of Intermediate I.1 (1.30 g; 4.79 mmol), (S)-tetrahydrofurfurylamine (0.989 ml; 9.59 mmol) and Hünig's base (1.65 ml; 9.59 mmol) in dioxane (20 ml) is stirred at 90° C. for 3 days, then evaporated. The residue is taken up in EE and washed with water. The organic layer is separated, dried (MgSO₄) and evaporated.

C₁₇H₂₄N₂O₆ ESI Mass spectrum: m/z=353 [M+H]+

HPLC analytics: RT=0.77 min (HPLC method A)

The following intermediates are prepared accordingly from the respective aryl halide and the respective nucleophilic reagent as indicated. Depending upon conditions applied, the syntheses may yield a free base, a TFA salt or other salt forms which can be applied equally to the syntheses of example compounds described below.

Nucleophlic reagent Intermediate Structure Aryl halide applied applied Synthesis comment II.2

ethylamine Reaction in DCM at r.t. II.3

1,3- benzylidene- glycerol Reaction at 80° C. overnight in DMF with K₂CO₃ added. Purifi- cation by RP-HPLC (modifier: TFA) II.4

II.3 2-(2-amino- ethoxy)- ethanol Reflux for 4 h in ACN with Cs₂CO₃ added. Purification by silica gel chromatography II.5

XIII.1 Reaction at 80° C. for 2 h in DMF with K₂CO₃ added. Purification by silica gel chromato- graphy II.6

II.5 2-(2-amino- ethoxy)- ethanol Reaction for 4 h in CAN at 106° C. (pres- sure vessel) with Cs₂CO₃ added.

Intermediate III.1

Intermediate II.1 (2.07 g; 5.87 mmol) in THF (20 ml) is hydrogenated in a Parr apparatus (r.t.; 3 bar hydrogen; catalyst: Raney-Nickel The catalyst is filtered off and the solvent is evaporated to obtain Intermediate III.1

The following intermediates are prepared accordingly from the respective aryl halide and the respective amine as indicated. Depending upon conditions applied, the syntheses may yield a free base, a TFA salt or other salt forms which can be applied equally to the syntheses of example compounds described below.

Nitro compound Intermediate Structure applied Synthesis comment III.2

VI.4 III.3

XI.1 Solvent: ethanol III.4

II.2 Solvent: ethanol; catalyst: Pd/C III.5

II.4 Solvent: methanol III.6

II.6 Solvent: methanol

Intermediate IV.1

Step 1: A mixture of Intermediate III. 1 (10.4 g; 32.2 mmol), the glycine derivative N-phthaloyl-glycine (6.62 g; 32.3 mmol), the coupling reagent TBTU (10.4 g; 32.3 mmol) and triethylamine (4.92 ml; 35.5 mmol) in THF (40 ml) is stirred at r.t. for 4 h. The mixture is poured on ice-water and the precipitate is filtered off, washed with water and dried at 65° C.

Step 2: The residue is taken up in dioxane (120 ml) and glacial acetic acid (30 mL) and stirred at 95° C. overnight. The solvent is evaporated. The residue is taken up in DCM and washed with water and Na—HCO₃ (sat. aq. solution). The organic layer is separated, dried and evaporated. The residue is purified by silica gel chromatography (eluent: DCM/methanol).

C₂₇H₂₉N₃O₆ ESI Mass spectrum: m/z=492 [M+H]+

The following intermediates are prepared accordingly from the glycine derivative N-phthaloyl-glycine and the respective diamino compound as indicated. Depending upon conditions applied, the syntheses may yield a free base, a TFA salt or other salt forms which can be applied equally to the syntheses of example compounds described below.

diamino com- pound Glycine deriv- Intermediate Structure applied ative applied Synthesis comment IV.2

III.2 N-BOC- glycine Step 2: reaction at 50° C. IV.3

III.3 N-phthaloyl- glycine Step 2: reaction in ace- tic acid at 80° C. for 2 h. IV.4

III.4 N-BOC- glycine Step 2: reaction in ace- tic acid at 60° C. for 12 h. IV.5

III.5 N-phthaloyl- glycine Step 2: reflux in acetic for 30 min. IV.6

III.6 N-phthaloyl- glycine Step 2: reflux in acetic for 30 min.

Intermediate V.1

Step 1: A mixture of the benzimidazole intermediate IV. 1 (0.20 g; 0.407 mmol), the alkylating agent iodoethane (296 μl; 3.66 mmol) and ACN (3 ml) is stirred at 120° C. for 6 h (closed vessel; microwave heating).

Step 2: Aq. HCl (4 mol/l; 4 ml) is added and the mixture is stirred at 50° C. for 4 h.

The mixture is evaporated to dryness.

C₂₅H₂₆N₃O₆×I ESI Mass spectrum: m/z=464 [M]+

HPLC analytics: RT=0.80 min (HPLC method B)

The following intermediates are prepared accordingly from the respective benzimidazole and alkylating agent as indicated. Depending upon conditions applied, the syntheses may yield a free base, a TFA salt or other salt forms which can be applied equally to the syntheses of example compounds described below.

Alkylating Benzimid- agent Intermediate Structure azole applied applied Synthesis comment V.2

IV.2 Iodo-ethane Reaction at r.t. for 3 days; step 2 omitted; purification by silica gel chromatography (DCM/ MeOH 0 -> 5%) V.3

V.2 Triethyl- oxonium tetra- fluoro- borate Reaction in DCM at r.t. for 30 min with 3 eq. of N-ethyl- dicyclohexyl-amine added. Step 2 omitted. Purification by RP- HPLC. V.4

IV.3 Iodo-ethane 1.3 eq. of sodium hydride added. Reaction at r.t. overnight. Step 2 omitted. V.5

V.4 Iodo-ethane Reaction at 90° C. overnight in DMF V.6

VI.5 Iodo-ethane Reaction at 80° C. overnight in DMF

Intermediate VI.1

A mixture of the carboxylic acid intermediate V.1 (0.30 g; 0.457 mmol), the amine intermediate VII. 1 (0.103 g; 0.457 mmol), TBTU (0.147 g; 0.457 mmol), triethylamine (255 μl; 1.83 mmol) and DMF (4 ml) is stirred at r.t. overnight, then evaporated. The crude product is purified by RP-HPLC (modifier: TFA).

C₃₃H₃₆N₅O₆×C₂F₃O₂ ESI Mass spectrum: m/z=598 [M]+

HPLC analytics: RT=0.39 min (HPLC method A)

The following intermediates are prepared accordingly from the respective diamino compound as indicated. Depending upon conditions applied, the syntheses may yield a free base, a TFA salt or other salt forms which can be applied equally to the syntheses of example compounds described below.

Carboxylic amine Intermediate Structure acid applied applied Synthesis comment VI.2

V.1 (S,S)-3,4- dihydroxy- pyrrolidine VI.3

V.1 4-amino-1- tert- butoxycar- bonyl- piperidine VI.4

2-amino- 5-bromo- 3-nitro- benzoic acid Bis(2- methoxy- ethyl)- amine Solvent: THF VI.5

A.1 IX.6 Coupling reagent: HATU VI.6

XII.1 N-BOC- 1,3- diamino- propane Coupling reagent: HATU VI.7

A.1 VIII.5 Coupling reagent: HATU

Intermediate VII.1

The compound is prepared according to the procedure described in: Stempel, Buzzi; Journal of the American Chemical Society 71 (1949) p. 2968 ff.

Intermediate VIII.1

A mixture of the phthalimide derivative intermediate VI. 1 (0.130 g; 0.183 mmol), hydrazine hydrate (44 μl; 0.913 mmol) and ACN (5 ml) is stirred at 60° C. overnight. Upon cooling to r.t., insolubles are filtered off, the filtrate is evaporated. The crude product is purified by RP-HPLC (modifier: TFA).

C₂₅H₃₄N₅O₄×CF₃COOH ESI Mass spectrum: m/z=469 [M+H]+

HPLC analytics: RT=0.27 min (HPLC method A)

The following intermediates are prepared accordingly from the phthalimide derivative as indicated. Depending upon conditions applied, the syntheses may yield a free base, a TFA salt or other salt forms which can be applied equally to the syntheses of example compounds described below.

Phthalimide derivative Intermediate Structure applied Synthesis comment VIII.2

VI.2 VIII.3

VI.3 VIII.4

V.5 Solvent: ethanol VIII.5

IV.5 Solvent: ethanol VIII.6

IV.6 reflux in ethanol for 1 h. No chromate- graphic purification.

Intermediate IX.1

A mixture of intermediate V.3 (0.700 g; 0.556 mmol), HCl (4 mol/1 in dioxane; 2.0 ml; 8.0 mmol) and dioxane (3.0 ml) is stirred at r.t. for 2 h, then evaporated to dryness.

C₁₉H₃₀N₅O₃×Cl×HCl

HPLC analytics: RT=0.34 min (HPLC method A)

The following intermediates are prepared accordingly from the intermediate as indicated. Depending upon conditions applied, the syntheses may yield a free base, a TFA salt or other salt forms which can be applied equally to the syntheses of example compounds described below.

intermediate Intermediate Structure applied Synthesis comment IX.2

X.1 IX.3

X.2 Solvent: ACN IX.4

X.3 Solvent: ACN IX.5

X.4 IX.6

IV.4 Reaction in HCl/ diethyl ether IX.7

V.6 Reflux in conc. aq. HCl for 4 h.

Intermediate X.1

A mixture of the aryl halide intermediate V.3 (1.20 g; 1.83 mmol), 1-(2-morpholinoethyl)-1H-pyrazole-4-boronic acid pinacol ester (0.731 g; 2.38 mmol), bis(triphenylphosphine)-palladium^((II))chloride (0.128 g; 0.138 mmol), Na₂CO₃ (0.291 g; 2.75 mmol), dioxane (3.0 ml) and water (0.1 ml) is stirred at 80° C. for 1 h. The mixture is filtered, evaporated, and the crude product is purified by RP-HPLC (modifier: TFA).

C₃₃H₅₂N₇O₆×C₂HF₃O₂×C₂F₃O₂ ESI Mass spectrum: m/z=642 [M]+

HPLC analytics: RT=0.75 min (HPLC method A)

The following intermediates are prepared accordingly from the aryl halide and the boronic ester as indicated. Depending upon conditions applied, the syntheses may yield a free base, a TFA salt or other salt forms which can be applied equally to the syntheses of example compounds described below.

Aryl halide Boronic ester Synthesis Intermediate Structure applied applied comment X.2

V.3

X.3

V.3

X.4

V.3

Intermediate XI.1

To a solution of intermediate 1.2 (11.8 g; 55.8 mmol) in ACN (200 ml) is added at 0° C. N-bromosuccinimide (10.9 g; 61.4 mmol). The mixture is stirred at 0° C. for 1 h, then water (200 ml) is added. The precipitate is filtered off with suction, washed with water and dried.

C₉H₁₁BrN₂O₄ ESI Mass spectrum: m/z=292 [M+H]+

HPLC analytics: RT=0.90 min (HPLC method I)

Intermediate XII.1

A mixture of intermediate VI.5 (150 mg; 0.359 mmol), aq. NaOH (1 mol/1; 1.10 ml; 1.10 mmol) and ethanol (3 ml) is stirred at 60° C. for 2 h. After cooling to r.t. aq. HCl (1 mol/1; 1.10 ml) is added. The precipitate is filtered off and dried.

C₁₆H₁₆ClN₇O₃

Intermediate XIII.1

To a mixture of glycolic acid (1.90 g; 25.0 mmol), EDC (25.4 mmol), HOBT (4.10 g; 30.3 mmol) and DCM (20 ml) is added at 0° C. 4-amino-piperidine-1-carboxylic acid tert-butyl ester (5.00 g; 25.0 mmol) and triethylamine (5.20 ml; 37.5 mmol). The mixture is stirred for 3 h, then extracted with water. The organic layer is separated, dried, filtered and evaporated. The crude product is purified by silica gel chromatography (DCM/MeOH 3->8%).

C₁₂H₂₂N₂O₄ ESI Mass spectrum: m/z=257 [M−H]−

Synthesis of Examples Example 1.01

The amine intermediate VIII.2 (160 mg; 0.150 mmol) is added to a mixture of intermediate A.1 (28.3 mg; 0.150 mmol), TBTU (48 mg; 0.15 mmol), triethylamine (84 μl; 0.60 mmol) and DMF (10.0 ml). The mixture is stirred at r.t. overnight, then evaporated and the crude product is purified by RP-HPLC (modifier: TFA).

C₂₆H₃₄ClN₈O×C₂F₃O₂ ESI Mass spectrum: m/z=589 [M]+

HPLC analytics: RT=0.38 min (HPLC method B)

The following example compounds are prepared accordingly from intermediate A.1 and the respective amine intermediate as indicated. Depending upon conditions applied, the syntheses may yield a TFA salt, a zwitterion or other salt forms.

Amine HPLC Example Structure applied M+ RT (min) method 1.02

VIII.4 526 0.62 H 1.03

VIII.1 638 0.38 A 1.04

IX.2 712 0.36 A 1.05

IX.3 708 0.36 A 1.06

IX.1 611 0.46 A 1.07

VIII.3 686 0.52 A 1.08

IX.4 627 0.45 A 1.09

IX.5 710 0.5 A

Example 2.01

The compound is prepared according to the procedure described for example 1.01 from intermediate A.2 and intermediate VII.2.

C₂₆H₃₄BrN₈O₆×C₂F₃O₂ ESI Mass spectrum: m/z=633 [M]+

HPLC analytics: RT=0.39 min (HPLC method A)

Example 3.01

The amine intermediate VII.1 (20 mg; 0.089 mmol) is added to a mixture of the acid intermediate IX.7 (35.0 mg; 0.077 mmol), HATU (35 mg; 0.092 mmol), triethylamine (30 mg; 0.296 mmol) and DMF (1.0 ml). The mixture is stirred at r.t. overnight, then evaporated. The crude product is purified by RP-HPLC (modifier: TFA). Methanolic HCl is added and the mixture is evaporated to dryness.

C₂₆H₃₁ClN₉O₃×Cl ESI Mass spectrum: m/z=552 [M]+

HPLC analytics: RT=0.33 min (HPLC method B)

The following example compounds are prepared accordingly from the respective amine and acid intermediate as indicated. Depending upon conditions applied, the syntheses may yield a chloride salt, a TFA salt, a zwitterion or other salt forms.

SM2 RT HPLC Example Structure SM cpd cpd M+ (min) method 3.02

4-amino-1-BOC- piperidine IX.7 600 0.51 A 3.03

N-BOC-1,3-diamino- propane IX.7 574 0.47 A 3.04

N-BOC-piperazine IX.7 586 0.50 A 3.05

2-(dimethyl-amino)- ethyl-amine IX.7 488 0.30 A

Example 4.01

A mixture of example 1.07 (95.0 mg; 0.119 mmol) and HCl (4 mol/l in dioxane; 1.0 ml) is stirred at r.t. for overnight, then evaporated. The crude product is purified by RP-HPLC (Modifier: TFA).

C₂₇H₃₇ClN₉O₄×C₂HF₃O₂×C₂F₃O₂ ESI Mass spectrum: m/z=586 [M]+

HPLC analytics: RT=0.35 min (HPLC method A)

The following example compounds are prepared accordingly from the respective BOC intermediate as indicated. Optionally, products are taken up in aq. HCl and evaporated to dryness. Depending upon conditions applied, the syntheses may yield a chloride salt, a TFA salt, a zwitterion or other salt forms.

HPLC Example Structure SM cpd M+ RT (min) method 4.02

3.04 486 0.3 A 4.03

3.02 500 0.3 A

Example 5.01

A mixture of the benzimidazole intermediate VI.7 (40.0 mg; 0.066 mmol), Iodoethane (100 μl; 1.24 mmol), Hünig's base (100 μl; 0.580 mmol) and ACN (2.0 ml) is heated to 120° C. for 6 h (closed vessel; microwave irradiation). The mixture is evaporated to dryness and the crude product is purified by RP-HPLC (modifier: TFA). The product is taken up in methanolic HCl and evaporated to dryness.

C₂₂H₃₁ClN₇O₆×Cl ESI Mass spectrum: m/z=524 [M]+

HPLC analytics: RT=0.67 min (HPLC method B)

Example 6.01

The product is prepared from intermediate VI.6 similar to the procedure described for example 5.01 with the difference that, before chromatographic purification, the crude product is stirred in DCM/TFA 5:1 at r.t. overnight.

C₂₁H₂₉ClN₉O₂×Cl×HCl ESI Mass spectrum: m/z=474 [M]+

HPLC analytics: RT=0.61 min (HPLC method B)

Example 7.01

The product is prepared from intermediate VIII.6 according to the procedure described for example 6.01.

C₂₆H₃₇ClN₉O₅×C₂F₃O₂

HPLC analytics: RT=0.65 min (HPLC method B)

Analytical Methods and Preparative Chromatography

As a rule, ¹H-NMR and mass spectra have been obtained for the compounds prepared. Mass peaks given (e.g. (M+H)+, (M+HCOO)—) refer to monoisotopic molecular weight. R_(f) values from TLC are determined using ready-made silica gel 60 TLC plates F₂₅₄ (E. Merck, Darmstadt, Item no. 1.05714) without chamber saturation or using ready-made aluminium oxide 60 F₂₅₄ TLC plates (E. Merck, Darmstadt, Item no. 1.05713) without chamber saturation. The ratios given for the eluents relate to units by volume of the solvent in question. The units by volume for NH₃ relate to a concentrated solution of NH₃ in water. For silica gel chromatographic purifications, silica gel from Millipore (MATREX™, 35-70 my) is used.

Preparative Thin Layer Chromatography (TLC):

Preparative TLC plates from Merck (PLC Silica gel 60 F₂₅₄₊₃₆₆, 2 mm) are used. Product containing bands are scraped off and the resulting product-on-silica powder is extracted with DCM, methanol or a mixture thereof (depending on product solubility). Silica is filtered off and the filtrate is evaporated to dryness to yield the purified compound.

Preparative HPLC:

Stationary phase (unless stated otherwise): XBridge C18; 10 μm or SunFire C18; 10 m (both from waters, www.waters.com)

Analytical HPLC/MS Methods

The HPLC retention times given are measured under the following parameters.

HPLC Method A

Column: SunFire C18, 2.1 × 30 mm, 2.5 μm (Waters) Gradient % Sol % Sol Flow Temp time [min] [H2O, 0.1% TFA] [ACN] [ml/min] [° C.] 0.00 99 1 1.5 60 0.02 99 1 1.5 60 1.00 0 100 1.5 60 1.10 0 100 1.5 60

HPLC Method B

Column: SunFire, 3 × 30 mm, 2.5 μm (Waters) Gradient % Sol % Sol Flow Temp time [min] [H2O, 0.1% TFA] [ACN] [ml/min] [° C.] 0.00 97 3 2.2 60 0.20 97 3 2.2 60 1.20 0 100 2.2 60 1.25 0 100 3 60 1.40 0 100 3 60

HPLC Method H

Column: XSELECT HSS PFP, 2.1 × 30 mm, 1.8 μm (Waters) Gradient/Solvent % Sol % Sol Flow Temp Time [min] [H2O, 0.1% TFA] [Acetonitril] [ml/min] [° C.] 0.0 99 1 1.5 60 0.02 99 1 1.5 60 1.00 0 100 1.5 60 1.10 0 100 1.5 60

HPLC Method I

Column: XBridge C18, 3 × 30 mm, 2.5 μm (Waters) Gradient/Solvent % Sol % Sol Flow Temp Time [min] [H2O, 0.1% TFA] [Acetonitril] [ml/min] [° C.] 0.00 97 3 2.2 60 0.20 97 3 2.2 60 1.20 0 100 2.2 60 1.25 0 100 3 60 1.40 0 100 3 60

The following abbreviations are used above and hereinafter:

-   ACN Acetonitrile -   BOC tert-Butoxycarbonyl -   Cbz Carbobenzyloxy -   CH Cyclohexane -   DCM Dichloromethane -   DIPEA Diisopropyl-ethylamine -   DMAP 4-Dimethylaminopyridine -   DMF N,N-Dimethylformamide -   DPPF 1,1′-Bis(diphenylphosphino)ferrocene -   EDC 1-Ethyl-3-(3-dimethylaminopropyl)carbodiimide hydrochloride -   EE Ethyl acetate -   Eq. Molar equivalent -   ESI Electrospray ionization -   h hour -   HATU O-(7-Azabenzotriazol-1-yl)-N,N,N′,N′-tetramethyluronium     hexafluorophosphate -   HCl Hydrochloric acid -   KOH Potassium hydroxide -   l litre -   LiHMDS Lithium bis(trimethylsilyl)amide -   M mol/l -   Min minutes -   Mp melting point -   NaOH Sodium hydroxide -   n.d. not determined -   NMP N-Methylpyrrolidone -   Pd/C palladium on charcoal -   r.t. ambient temperature (about 20° C.) -   RT retention time -   TBME Methyl tert-butyl ether -   TBTU     2-(1H-Benzotriazol-1-yl)-1,1,3,3-tetramethyluronium-tetrafluoroborate -   TEA Triethylamine -   TFA Trifluoroacetic acid -   THF Tetrahydrofurane -   TLC Thin Layer Chromatography -   TMS Trimethylsilyl

Pharmacological Test Method

The IC₅₀ values of the example compounds given above were determined in the Ussing Chamber assay.

Ussing Chamber: Mouse kidney M-1 cells were cultivated in DMEM containing 5% FCS and 5 M dexamethasone for 10 to 12 days on polyester transwell filters. Filters were inserted into a teflon-coated well-plate which fit into the ussing chamber system. Prior to measurement the medium of M-1 cells was replaced with Caco-2 transport buffer (Invitrogen, Germany). During measurements, the Ussing chamber temperature was kept at 37° C. Short circuit currents (I_sc) were measured in the voltage-clamp mode with the software package Lab View for data acquisition and analysis. The transepithelial electrical re-sistance (TEER) was determined by the application of voltage steps of ±5 mV every 5 sec. Compounds were administered at a final concentration of 3 μM or at increasing concentrations (1-3-10 μM) to the apical solution. At the end of each experiment the amiloride sensitive I_SC was measured by adding 3 M amiloride to the apical compartment. Results are expressed as inhibition in percent of the amiloride effect or as IC₅₀.

With the example compounds given above, the following IC₅₀ values were determined in the Ussing Chamber assay:

Example 1.01 1.03 1.07 2.01 3.01 3.02 3.03 3.04 3.05 4.01 4.02 4.03 IC₅₀ [nM] 36 31 2 24 2 3 5 3 6 1 3 5 Example 5.01 6.01 7.01 IC₅₀ [nM] 16 5 11

Permeability in CALU-3 Cells:

Permeability measurements across polarized, confluent CALU-3 cell monolayers grown on permeable filter supports are used to provide information on the potential of a compound to pass the lung epithelium. Apparent permeability coefficients (Papp) of the compounds across the CALU-3 cell monolayers are measured (pH 7.4, 37° C.) in apical-to-basal (AB) and basal-to-apical (BA) transport direction. AB permeability (Papp, AB) represents drug absorption from the lung lumen into the blood and BA permeability (Papp, BA) drug transport from the blood into the lung lumen mainly via passive permeability since Calu-3 cells as well as lung epithelial cells do not express efflux transporters like P-gp, while uptake transporters may be expressed.

CALU-3 cells (1-2×10⁵ cells/1 cm² area) are seeded on filter inserts (Costar transwell polycarbonate filters, 0.4 m pore size) and cultured (for 10-12 days DMEM) until tight monolayers are formed. Compounds of interest are dissolved in appropriate solvent (DMSO, 10 mM stock solution). Stock solutions are diluted with HTP-4 buffer (128.13 mM NaCl, 5.36 mM KCl, 1 mM MgSO4, 1.8 mM CaCl2, 4.17 mM NaHCO3, 1.19 mM Na2HPO4×7H2O, 0.41 mM NaH2PO4×H2O, 15 mM HEPES, 20 mM glucose, 0.25% BSA, pH 7.4) to prepare the transport solutions (10 μM compound, final DMSO<=0.5%). The transport solution (TL) is applied to the apical or basolateral donor side for measuring A-B or B-A permeability (3 filter replicates), respectively. The receiver side contains the same buffer as the donor side. After 30 min of accommodation, samples are collected at the start t0=0 min and at the end of the experiment tn=90 min from the donor and at 0, 30, 60, and 90 min also from the receiver chamber. Volume removed is replenwashed by HTP-4 buffer. The compound concentration in the samples is measured by s5 HPLC-MS/MS or scintillation counting. The permeability coefficient (Papp) and efflux ratio are calculated according to: Papp [cm/s]=(concentration receiver [nM]*volume receiver [mL]/time interval [sec])*(1/filter area)*(1/donor concentration [nM]).

With example compounds given above, the following permeability values were determined in the CALU-3 cells assay:

Example 1.03 2.01 3.05 4.01 4.02 4.03 6.01 Papp, AB 0.3 0.2 0.04 0.3 0.2 0.08 0.1 [10⁻⁶ cm/s] Papp, BA 0.5 0.2 0.06 0.3 0.1 0.1 0.09 [10⁻⁶ cm/s]

Indications

As has been found, the compounds of formula (I) are characterised by their wide range of applications in the therapeutic field. Particular mention should be made of those applications for which the compounds according to the invention of formula (I) are preferably suited on account of their pharmaceutical efficacy as ENaC inhibitors. Examples include respiratory diseases or complaints, or allergic diseases of the airways.

Particular mention should be made of the prevention and treatment of diseases of the airways and of the lung which are accompanied by increased mucus production, inflammations and/or obstructive diseases of the airways. Examples include acute, allergic or chronic bronchitis, chronic obstructive bronchitis (COPD), coughing, pulmonary emphysema, allergic or non-allergic rhinitis or sinusitis, chronic rhinitis or sinusitis, asthma, alveolitis, Farmer's disease, hyperreactive airways, infectious bronchitis or pneumonitis, paediatric asthma, bronchiectases, pulmonary fibrosis, ARDS (acute adult respiratory distress syndrome), bronchial oedema, pulmonary oedema, bronchitis, pneumonia or interstitial pneumonia triggered by various causes, such as aspiration, inhalation of toxic gases, or bronchitis, pneumonia or interstitial pneumonia as a result of heart failure, irradiation, chemotherapy, cystic fibrosis or mucoviscidosis, or al-phal-antitrypsin deficiency.

Particularly preferably the present invention relates to the use of compounds of formula (I) for preparing a pharmaceutical composition for the treatment of inflammatory or obstructive diseases of the upper and lower respiratory tract including the lungs, such as for example allergic rhinitis, chronic rhinitis, bronchiectasis, cystic fibrosis, COPD, chronic bronchitis, chronic sinusitis and asthma.

It is most preferable to use the compounds of formula (I) for the treatment of inflammatory and obstructive diseases such as COPD, chronic bronchitis, chronic sinusitis, asthma, cystic fibrosis, particularly COPD, chronic bronchitis, asthma and cystic fibrosis.

The actual pharmaceutically effective amount or therapeutic dosage will of course depend on factors known by those skilled in the art such as age and weight of the patient, route of administration and severity of disease. In any case the combination will be administered at dosages and in a manner which allows a pharmaceutically effective amount to be delivered based upon patient's unique condition.

Combinations

The compounds of formula (I) may be used on their own or in conjunction with other active substances of formula (I) according to the invention. If desired the compounds of formula (I) may also be used in combination with other pharmacologically active substances.

Therefore the invention further relates to medicament combinations which preferably contain, besides one or more compounds of formula (I) or a salt thereof, as further active substances, one or more compounds selected from among the categories of further ENaC inhibitors, betamimetics, anticholinergics, corticosteroids, PDE4-inhibitors, LTD4-antagonists, EGFR-inhibitors, dopamine agonists, H1-antihistamines, PAF-antagonists, MAP-kinase inhibitors, MPR4-Inhibitors, iNOS-Inhibitors, SYK-Inhibitors, corrections of the cystic fibrosis transmembrane regulator (CFTR) and CFTR potentiators, or double or triple combinations thereof.

Formulations

Suitable forms for administration are for example inhalable powders or aerosols. The content of the pharmaceutically effective compound(s) in each case should be in the range from 0.2 to 50 wt %, preferably 5 to 25 wt % of the total composition, i.e. in amounts which are sufficient to achieve the dosage range specified hereinafter.

Administered by inhalation the active substance combination may be given as a powder, as an aqueous or aqueous-ethanolic solution or using a propellant gas formulation.

Preferably, therefore, pharmaceutical formulations are characterised in that they contain one or more compounds of formula (I) according to the preferred embodiments above.

It is also preferred if the compounds of formula (I) are administered by inhalation, particularly preferably if they are administered once or twice a day. For this purpose, the compounds of formula (I) have to be made available in forms suitable for inhalation. Inhalable preparations include inhalable powders, propellant-containing metered-dose aerosols or propellant-free inhalable solutions, which are optionally present s1 in admixture with conventional physiologically acceptable excipients.

Within the scope of the present invention, the term propellant-free inhalable solutions also include concentrates or sterile ready-to-use inhalable solutions. The preparations which may be used according to the invention are described in more detail in the next part of the specification.

Inhalable Powders

If the active substances of formula (I) are present in admixture with physiologically acceptable excipients, the following physiologically acceptable excipients may be used to prepare the inhalable powders according to the invention: monosaccharides (e.g. glucose or arabinose), disaccharides (e.g. lactose, saccharose, maltose), oligo- and polysaccharides (e.g. dextran), polyalcohols (e.g. sorbitol, mannitol, xylitol), salts (e.g. sodium chloride, calcium carbonate) or mixtures of these excipients with one another. Preferably, mono- or disaccharides are used, while the use of lactose or glucose is preferred, particularly, but not exclusively, in the form of their hydrates. For the purposes of the invention, lactose is the particularly preferred excipient, while lactose monohydrate is most particularly preferred. Methods of preparing the inhalable powders according to the invention by grinding and micronising and by finally mixing the components together are known from the prior art.

Propellant-Containing Inhalable Aerosols

The propellant-containing inhalable aerosols which may be used according to the invention may contain a compound of formula (I) dissolved in the propellant gas or in dispersed form. The propellant gases which may be used to prepare the inhalation aerosols according to the invention are known from the prior art. Suitable propellant gases are selected from among hydrocarbons such as n-propane, n-butane or isobutane and halohydrocarbons such as preferably fluorinated derivatives of methane, ethane, propane, butane, cyclopropane or cyclobutane. The propellant gases mentioned above may be used on their own or in mixtures thereof. Particularly preferred propellant gases are fluorinated alkane derivatives selected from TG134a (1,1,1,2-tetrafluoroethane), TG227 (1,1,1,2,3,3,3-heptafluoropropane) and mixtures thereof. The propellant-driven inhalation aerosols used within the scope of the use according to the invention may also contain other ingredients such as co-solvents, stabilisers, surfactants, antioxidants, lubricants and pH adjusters. All these ingredients are known in the art.

Propellant-Free Inhalable Solutions

The compounds of formula (I) according to the invention are preferably used to prepare propellant-free inhalable solutions and inhalable suspensions. Solvents used for this purpose include aqueous or alcoholic, preferably ethanolic solutions. The solvent may be water on its own or a mixture of water and ethanol. The solutions or suspensions are adjusted to a pH of 2 to 7, preferably 2 to 5, using suitable acids. The pH may be adjusted using acids selected from inorganic or organic acids. Examples of particularly suitable inorganic acids include hydrochloric acid, hydrobromic acid, nitric acid, sulphuric acid and/or phosphoric acid. Examples of particularly suitable organic acids include ascorbic acid, citric acid, malic acid, tartaric acid, maleic acid, succinic acid, fumaric acid, acetic acid, formic acid and/or propionic acid etc. Preferred inorganic acids are hydrochloric and sulphuric acids. It is also possible to use the acids which have already formed an acid addition salt with one of the active substances. Of the organic acids, ascorbic acid, fumaric acid and citric acid are preferred. If desired, mixtures of the above acids may also be used, particularly in the case of acids which have other properties in addition to their acidifying qualities, e.g. as flavourings, antioxidants or complexing agents, such as citric acid or ascorbic acid, for example. According to the invention, it is particularly preferred to use hydrochloric acid to adjust the pH.

Co-solvents and/or other excipients may be added to the propellant-free inhalable solutions used for the purpose according to the invention. Preferred co-solvents are those which contain hydroxyl groups or other polar groups, e.g. alcohols—particularly isopropyl alcohol, glycols—particularly propyleneglycol, polyethyleneglycol, polypropyleneglycol, glycolether, glycerol, polyoxyethylene alcohols and polyoxyethylene fatty acid esters. The terms excipients and additives in this context denote any pharmacologically acceptable substance which is not an active substance but which can be formulated with the active substance or substances in the pharmacologically suitable solvent in order to improve the qualitative properties of the active substance formulation. Preferably, these substances have no pharmacological effect or, in connection with the desired therapy, no appreciable or at least no undesirable pharmacological effect. The excipients and additives include, for example, surfactants such as soya lecithin, oleic acid, sorbitan esters, such as polysorbates, polyvinylpyrrolidone, other stabilisers, complexing agents, antioxidants and/or preservatives which guarantee or prolong the shelf life of the finwashed pharmaceutical formulation, flavourings, vitamins and/or other additives known in the art. The additives also include pharmacologically acceptable salts such as sodium chloride as isotonic agents. The preferred excipients include antioxidants such as ascorbic acid, for example, provided that it has not already been used to adjust the pH, vitamin A, vitamin E, tocopherols and similar vitamins or provitamins occurring in the human body. Preservatives may be used to protect the formulation from contamination with pathogens. Suitable preservatives are those which are known in the art, particularly cetyl pyridinium chloride, benzalkonium chloride or benzoic acid or benzoates such as sodium benzoate in the concentration known from the prior art.

For the treatment forms described above, ready-to-use packs of a medicament for the treatment of respiratory complaints are provided, containing an enclosed description including for example the words respiratory disease, COPD or asthma, a compound according to the invention and one or more combination partners selected from those described above. 

1. A compound of formula (I), or a tautomer thereof or a pharmacologically acceptable acid addition salt of the compound or the tautomer,

wherein R¹ is selected from C₁-C₃-alkyl, tetrahydrofurylmethyl, and H(OCH₂CH₂)_(n), wherein n is 1, 2, or 3; R² is selected from C₁-C₃-alkyl; R³ is selected from —C(O)NR_(a)R_(b), —CH₂—C(O)NR_(a)R_(b), and —O—CH₂—C(O)NR_(a)R_(b), wherein at least one R^(a) or R^(b) is selected from C₁-C₂-alkoxy-C₂-C₃-alkyl, amino-C₂-C₃-alkyl, 4-piperidinyl, dimethylamino-C₂-C₃-alkyl, 1-(C₁-C₄-alkoxycarbonylamino)-C₂-C₃-alkyl, 1-(C₁-C₄-alkoxy-carbonyl)-4-piperidinyl, 3-hydroxy-2-pyridylmethyl and 3-hydroxy-6-methyl-2-pyridylmethyl; and wherein the remaining substituent R^(a) or R^(b) may additionally be selected from H, C₁-C₃-alkyl, hydroxyethyl, or hydroxypropyl; or wherein R^(a) and R^(b) together with the nitrogen atom they are attached to form a heterocyclic ring selected from piperazine, and pyrrolidine, wherein the heterocyclic ring may carry 1 or 2 substituents selected from methyl, OH, and C₁-C₄-alkoxycarbonyl; or wherein R³ is selected from C₁-C₃-alkoxy substituted by 1 or 2 substituents selected from OH and C₁-C₃-alkoxy; R⁴ is selected from H, Cl, Br, pyrrolyl, pyridinyl, and N-morpholinyl, wherein pyrrolyl, and pyridinyl may optionally carry 1 or 2 substituents selected from C₁-C₃-alkyl, 1-methylpiperazin-4-yl, tetrahydropyran-4-yloxy), and morpholin-4-yl-C₂-C₃-alkyl; X is Cl or Br; and Z⁻ is chloride, bromide, iodide, hydroxide, hydrogensulfate, sulfate, nitrate, phosphate, formate, acetate, trifluoroacetate, fumarate, citrate, tartrate, oxalate, succinate, mandelate, methanesulfonate or p-toluenesulfonate; or Z− may be absent if the remaining compound of formula (I) carries at least one negatively charged substituent R³ or R⁴.
 2. The compound of formula (I) according to claim 1, or a tautomer thereof or a pharmacologically acceptable acid addition salt of the compound or the tautomer, wherein R³ is selected from —C(O)NR_(a)R_(b).
 3. The compound of formula (I) according to claim 2, or a tautomer thereof or a pharmacologically acceptable acid addition salt of the compound or the tautomer, wherein R³ is selected from

wherein

denotes the point of attachment.
 4. The compound of formula (I) according to claim 1, or a tautomer thereof or a pharmacologically acceptable acid addition salt of the compound or the tautomer, wherein R³ is selected from —O—CH₂—C(O)NR_(a)R_(b).
 5. The compound of formula (I) according to claim 4, or a tautomer thereof or a pharmacologically acceptable acid addition salt of the compound or the tautomer, wherein R³ is selected from

wherein

denotes the point of attachment.
 6. The compound of formula (I) according to claim 1, or a tautomer thereof or a pharmacologically acceptable acid addition salt of the compound or the tautomer, wherein R³ is selected from 1-hydroxymethyl-2-hydroxyethoxy and 2-methoxyethoxy.
 7. The compound of formula (I) according to claim 1, or a tautomer thereof or a pharmacologically acceptable acid addition salt of the compound or the tautomer, wherein R⁴ is selected from 1,3-dimethylpyrazol-4-yl, 1-(morpholin-4-yleth-2-yl)pyrazol-4-yl, pyridinyl, methylpyridinyl, 2-(1-methylpiperazin-4-yl)pyridin-5-yl, and 2-(tetrahydropyran-4-yloxy)pyridin-5-yl.
 8. The compound of formula (I) according to claim 1, or a tautomer thereof or a pharmacologically acceptable acid addition salt of the compound or the tautomer, wherein Z⁻ is chloride, or trifluoroacetate or Z⁻ may be absent if the remaining compound of formula (I) carries at least one negatively charged substituent R³ or R⁴.
 9. (canceled)
 10. A method of treating a disease comprising administering an effective amount of a compound according to claim 1 or a tautomer thereof or a pharmacologically acceptable acid addition salt of the compound or the tautomer, wherein the disease is selected from the group consisting of a respiratory disease, a respiratory complaint, and an allergic disease of the airways.
 11. A method of treating a disease comprising administering an effective amount of a compound according to claim 1 or a tautomer thereof or a pharmacologically acceptable acid addition salt of the compound or tautomer, wherein the disease is selected from the group consisting of chronic bronchitis, acute bronchitis, bronchitis caused by bacterial or viral infection or fungi or helminths, allergic bronchitis, toxic bronchitis, chronic obstructive bronchitis (COPD), asthma (intrinsic or allergic), pediatric asthma, bronchiectasis, allergic alveolitis, allergic or non-allergic rhinitis, chronic sinusitis, cystic fibrosis or mucoviscidosis, alpha-1-antitrypsin deficiency, cough, pulmonary emphysema, interstitial lung diseases, alveolitis, hyperreactive airways, nasal polyps, pulmonary oedema, pneumonitis of different origins, and dry eyes.
 12. A pharmaceutical composition comprising a compound according to claim 1 or a tautomer thereof or a pharmacologically acceptable acid addition salt of the compound or the tautomer and a pharmaceutically acceptable carrier.
 13. A pharmaceutical composition comprising a compound according to claim 1, or a tautomer thereof or a pharmacologically acceptable acid addition salt of the compound or the tautomer, and one or more compounds selected from the group consisting of an ENaC inhibitor, a betamimetic, an anticholinergic, a corticosteroid, a PDE4-inhibitor, an LTD4-antagonist, an EGFR-inhibitor, a dopamine agonist, an H1 antihistamine, a PAF-antagonist, a MAP-kinase inhibitor, a MPR4-Inhibitor, an iNOS-Inhibitor, a SYK-Inhibitor, a cystic fibrosis transmembrane regulator (CFTR) potentiator, and double or triple combinations thereof. 